in tetrahydrofuran (Ar); standard Schlenk technique; soln. of Fe complex in THF was added to W complex; mixt. was stirred at room temp. for 24 h; W complex (5 equiv.) was added; reacted for 2 d; solvent stripped out (vac.); sublimed; chromd. (alumina, petroleum ether; CH2Cl2; CH2Cl2/CH3CN, 1/1); elem. anal.;